Cutting method using diamond cutting tool

Abstract

Provided is a cutting method of cutting, with a diamond cutting tool, a metal material having at least a solid solution layer on a surface, the solid solution layer containing nitrogen atoms as interstitial solid solution atoms. In this method, cutting is performed in a region where a nitrogen concentration is equal to or greater than a predetermined concentration, and cutting is not performed in a region where the nitrogen concentration is less than the predetermined concentration.

What is claimed is: 
     
       1. A cutting method comprising cutting with a diamond cutting tool that is worn due to movement of carbon atoms to a to-be-cut object,
 cutting a solid solution layer of a metal material from a surface of the metal material with the diamond cutting tool, the metal material having at least the solid solution layer on the surface, the solid solution layer containing nitrogen atoms as interstitial solid solution atoms, 
 wherein the cutting is performed in a region where a nitrogen concentration is equal to or less than a predetermined first concentration and is equal to or greater than a predetermined second concentration, and the cutting is not performed in a region where the nitrogen concentration is less than the predetermined second concentration. 
 
     
     
       2. A cutting method comprising cutting with a diamond cutting tool that is worn due to movement of carbon atoms to a to-be-cut object,
 cutting a solid solution layer of a metal material from a surface of the metal material with the diamond cutting tool, the metal material having at least the solid solution layer on the surface, the solid solution layer containing nitrogen atoms as interstitial solid solution atoms, 
 after cutting a portion exhibiting a peak of nitrogen concentration that is equal to or less than a predetermined first concentration, the cutting is terminated before reaching a region where the nitrogen concentration is less than a predetermined second concentration. 
 
     
     
       3. The cutting method according to  claim 1 , wherein
 a surface of the solid solution layer is in a state where nitrogen atoms are incorporated in a saturated manner, and 
 the predetermined second concentration is determined based on a nitrogen concentration in the saturated region. 
 
     
     
       4. The cutting method according to  claim 3 , wherein
 the predetermined second concentration is determined to be equal to or greater than 70% of the nitrogen concentration in the saturated region. 
 
     
     
       5. A cutting method comprising cutting with a diamond cutting tool that is worn due to movement of carbon atoms to a to-be-cut object,
 cutting a solid solution layer of a metal material from a surface of the metal material with the diamond cutting tool, the metal material having at least the solid solution layer on the surface, the solid solution layer containing nitrogen atoms as interstitial solid solution atoms, 
 a region where a nitrogen concentration is equal to or less than a predetermined first concentration and is equal to or greater than a second concentration is defined as a cutting-allowed range, and the cutting is performed in a region where the nitrogen concentration is equal to or greater than a third concentration greater than the second concentration. 
 
     
     
       6. The cutting method according to  claim 5 , wherein
 a surface of the solid solution layer is in a state where nitrogen atoms are incorporated in a saturated manner, and 
 the second concentration is determined based on a nitrogen concentration in the saturated region. 
 
     
     
       7. The cutting method according to  claim 6 , wherein
 the second concentration is determined to be equal to or greater than 70% of the nitrogen concentration in the saturated region. 
 
     
     
       8. The cutting method according to  claim 1 , wherein
 the cutting method is a method of mirror-finishing the metal material. 
 
     
     
       9. The cutting method according to  claim 1 , wherein
 the metal material is an iron-based material. 
 
     
     
       10. The cutting method according to  claim 1 , wherein
 the first concentration serves as an upper limit of concentration without nitrides of the metal material. 
 
     
     
       11. The cutting method according to  claim 10 , wherein
 when the metal material is an iron-based material, the first concentration is 6 percent by weight.